| Abstract
| - This study provides a comparison of the rates of adsorption of the following thiols onto the surface ofgold: 1,2-bis(mercaptomethyl)-4,5-dihexadecylbenzene (1), 1-mercaptomethyl-3,4-dihexadecyl-benzene (2),hexadecanethiol (4a), and and eicosanethiol (4b). This study also compares the rates of adsorption of theseadsorbates to those obtained for the aromatic disulfide analogue of 1 (2,3-dithia-6,7-dihexadecyltetralin,3) and the normal dialkyl disulfide analogues of 4a and 4b (hexadecyl disulfide, 5a, and eicosyl disulfide,5b, respectively). The adsorption behavior was monitored using ex situ ellipsometry and polarizationmodulation infrared reflection absorption spectroscopy (PM-IRRAS). The adsorption profiles suggest thatmonolayer formation proceeds via two distinct kinetic regimes: (1) a fast initial adsorption, where ca.80−90% of the monolayer forms during the first few minutes of immersion, followed by (2) a slowerorientational ordering lasting several hours. Comparison of the rates of adsorption of the aromatic dithiols1 to those of aromatic monothiol 2 and normal alkanethiols 4a and 4b reveals that the structure of theadsorbate plays a substantial role during the initial stages of thiol adsorption. The impact of structuraland/or chemical variations is further illustrated by comparing the poor quality of the monolayer generatedfrom the aromatic disulfide 3 to those of monolayers generated from 1, 2, 4, and 5.
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